LIMA (Reuters) - Peru's finance and mines ministers presented their resignations to President Ollanta Humala following a cabinet spat over the minimum wage that has already pushed the prime minister from power, sources told Reuters on Monday.

Finance Minister Luis Miguel Castilla, a former World Bank economist who has been widely praised by investors, is resigning from Humala's cabinet after two and a half years, three government sources said.

Energy and Mines Minister Jorge Merino has also requested to leave his position as one of the top managers of the country's vast mineral wealth, a government source and an energy industry source said.

The sources spoke on condition of anonymity given the sensitivity of the topic.

Sources who said Castilla and Merino are resigning did not specify why the ministers want to leave. The ministers were not immediately available for comment.

Humala has not confirmed if he has accepted the resignations of Castilla and Merino, who have remained in power despite several cabinet reshuffles. Both helped reassure investors that Humala, a former left-leaning military officer, would continue to rely on orthodox policies to manage the fast-growing country's economy.

Earlier on Monday, Villanueva said on Peruvian TV that Humala accepted his resignation. His announcement came after he told a local newspaper last week that he was working on an effort to raise the minimum wage with the finance ministry.

Castilla and First Lady Nadine Heredia, a close adviser to Humala, stridently denied that the government was working on raising the minimum wage.

Castilla's rebuttal on TV late on Sunday was widely interpreted as a way to embarrass Villanueva and push him from power after just four months.

Humala has not yet commented on the cabinet dispute.

However, a swearing in of new ministers has been scheduled for late on Monday

Humala raised the minimum wage twice, to 750 soles (160 pounds) per month, after being elected on promises to make sure more Peruvians benefit from the country's mineral exports.

Villanueva is the fourth cabinet chief to resign from the government of Humala, who started the second half of his five-year term in January with a 26 percent approval rating - one of the lowest marks since being elected in 2011.